WebBrowser中html元素如何触发winform事件

WebBrowser中html元素如何触发winform事件?
这个问题来自论坛提问，对dom稍微了解的话还是比较简单的，只要注册一下事件就可以了。

C#代码如下:

using System;
using System.ComponentModel;
using System.Windows.Forms;

namespace WindowsApplication5
...{
    public partial class Form1 : Form
    ...{
        public Form1()
        ...{
            InitializeComponent();
        }
      

        private void Form1_Load(object sender, EventArgs e)
        ...{
            this.webBrowser1.Navigate("www.google.cn");
            this.webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
        }

        void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        ...{
            if (e.Url.ToString() != this.webBrowser1.Url.ToString()) return;
           foreach(System.Windows.Forms.HtmlElement el in  this.webBrowser1.Document.GetElementsByTagName("input"))
           ...{
               if (el.Name == "btnG")
               ...{
                   el.Click += new HtmlElementEventHandler(Form1_Click);
               }
           }
           
        }

        void Form1_Click(object sender, HtmlElementEventArgs e)
        ...{
            MessageBox.Show("jinjazz pass");
        }

    }
}